Graded treadmill exercise testing was performed in 52 symptomatic patients with aortic regurgitation (AR). Exercise capacity did not correlate with any hemodynamic or echocardiographic index of left ventricular (LV) function or size. However, among patients with echocardiographic evidence of LV systolic dysfunction (LV systolic dimension greater than 55 mm or fractional shortening less than or equal to 25%), patients with good exercise capacity preoperatively had improvement in systolic function postoperatively, while patients with poor exercise capacity preoperatively had further deterioration of systolic function postoperatively. Postoperative survival was significantly greater (p less than .05) in patients with LV systolic dysfunction with good exercise capacity compared to those with poor exercise capacity. Preoperative exercise testing is imprecise in assessing LV function in symptomatic patients with AR, but in combination with echo data is useful in predicting the outcome of subsequent operation and the reversibiliy of LV systolic dysfunction.